Fence rail cap



FIG. 1 is a perspective view of the design of the of the fence rail cap;

FIG. 2 is a right side view of the fence rail cap, which is a mirror image of the left side view of the fence rail cap;

FIG. 3 is a front sectional view of the fence rail cap, which is a mirror image of the rear sectional view of the fence rail cap;

FIG. 4 is a top plan view of the fence rail cap; and,

FIG. 5 is a bottom view of the fence rail cap. 

I claim the ornamental design for a fence rail cap, as shown and described. 